Help!

Jasmine • sc: zemblanitous
Alright ladies, got a questions for you. Fair warning it'll be semi graphic. 
So! I recently got my nexplanon birth control taken or, having that, it stopped my period. Haven't had one in almost a year. But once it was out, I should have started. Still haven't. 
Got down with a stud, used condoms. Butttt, about four or five days after my boobs started aching! My nipples are so sore, can't bump them on anything. 
It's been a couple weeks now of the sore tatas. Today though, I went to the bathroom, and when I wiped totally thought it would just be urine! But then a big ol piece of mucus came out. With a smudge of blood on it. Never had this happen before. If when I did get my period. 
Best friend thinks I'm pregnant, so taking a test today. Thoughts?!